Single die stitch bonding

ABSTRACT

An integrated circuit device comprising an integrated circuit die mounted on a leadframe having a plurality of inner leads. The integrated circuit die has a plurality of bond pads that are electrically connected to the inner leads of the leadframe, wherein at least two bond pads are connected to a one of the plurality of inner leads and/or at least two inner leads are connected to one or more bond pads with a single bond wire. A single bond wire is connected to a first bond pad or inner lead and subsequently wedge or stitch bonded to a second bond pad or inner lead, then it is connected to a third bond pad or inner lead. The single bond wire requires only one connection area at each of the bond pad(s) and inner lead(s). The bond pad(s) of the die and inner lead(s) of the leadframe are thereby electrically connected together by the single bond wire.

RELATED PATENT APPLICATION

[0001] This application is related to commonly owned U.S. patentapplication Ser. No. 09/832,287, entitled “Arrangement and Method ofArrangement of Stacked Dice in an Integrated Electronic Device” byJoseph Fernandez, filed Apr. 10, 2001, and is hereby incorporated byreference herein for all purposes.

FIELD OF THE INVENTION

[0002] The present invention is related to connecting to integratedcircuit bond pads, and more particularly to connecting related bond padsby stitch bonding a continuous bond wire thereto.

BACKGROUND OF THE INVENTION TECHNOLOGY

[0003] An Integrated circuit device may comprise an semiconductorintegrated circuit die mounted on a leadframe. The semiconductorintegrated circuit die comprises a plurality of bond pads that areelectrically connected to inner leads of the leadframe, e.g., using bondwires. The semiconductor integrated circuit die, the inner portion ofthe leadframe (inner leads) and the bond wires may be encapsulated intoan integrated circuit package. After encapsulation, a border or frame onthe outer portion of the leadframe is cut to separate outer leads of theleadframe into connecting pins or surface mount contacts which are usedto electrically connect the electronic circuitry in the semiconductorintegrated circuit die with other externally arranged electroniccomponents mounted on a substrate or printed circuit board.

[0004] Integrated circuit devices are becoming more and moresophisticated while integrated circuit package size and the number ofavailable package connections are being reduced. Limiting the number ofpackage connections available for connecting to device circuits isnecessary for both size and cost constraints. However, this may create aproblem for the integrated circuit device manufacturer who must offerintegrated circuit devices for many different types of configurationsand applications. Integrated circuit device cost is reduced when a largequantity of the same device is produced. It is relatively easy tofabricate an integrated circuit device capable of many differentconfigurations and uses than to have to perform various different metalmask operations so as to fabricate differently configured integratedcircuit devices. A specific device configuration may then be selectedduring fabrication of the integrated circuit device with the leadframeby appropriate jumper connections between the die bond pads and innerlead fingers of the leadframe. Typically, various combinations of diebond pads are connected together through common connections to an innerlead(s) of the leadframe. However selecting a specific configuration inthis fashion for configuration of the integrated circuit device becomesproblematic when the reduced die, package and leadframe areas availablefor interconnecting option selection pads of the integrated circuit dieare reduced. Making more than one wirebond connection to a die bond padand/or inner lead of a leadframe may not be practical or even possiblein the smaller and more densely packaged integrated circuits.

[0005] Therefore, there is a need for connecting a plurality ofintegrated circuit bond pads and/or inner leads of a leadframe togetherwithout requiring multiple connections thereto.

SUMMARY OF THE INVENTION

[0006] The present invention overcomes the above-identified problems aswell as other shortcomings and deficiencies of existing technologies byproviding multiple common connections in an integrated device whilerequiring only a single connection point at each of the commonlyconnected integrated circuit die bond pads and/or inner leads of aleadframe. A single wire is stitch or wedge bonded between one or moredie bond pads and one or more inner leads of a leadframe to create acommon connection therebetween.

[0007] According to an exemplary embodiment of the invention, anintegrated device comprising an integrated circuit die having bond padsand a leadframe having a plurality of inner leads may have multiplecommon connections between one or more of the die bond pads and one ormore of the inner leads of the leadframe. A single bond wire is wedge orstitch bonded to each of the one or more die bond pads and one or moreinner leads of a leadframe that are desired to be commonly connectedwhile requiring only a single attachment point at each of these one ormore die bond pads and these one or more inner leads.

[0008] A technical advantage of the present invention is using a singlewire stitch bond to create a common interconnection between one or moredie bond pads and/or one or more inner leads of a leadframe. Anothertechnical advantage is requiring only a single stitch bond wire to setdevice configuration. Still another technical advantage is a needingonly a single point of connection to a die bond pad and/or inner lead ofa leadframe for multiple common interconnections of one or more die bondpads and/or one or more inner leads of a leadframe. Yet anothertechnical advantage is reducing the number of different metal maskconfigurations required for selecting device operating modes.

[0009] A feature of the present invention is the ability to add optionsto the integrated circuit package after wafer fabrication. Anotherfeature is setting device mode options after wafer fabrication. Yetanother feature is using only one connection point at each bond pad andinner lead of a leadframe.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features and advantages of the invention will be apparent fromthe following description of presently preferred embodiments, given forthe purpose of disclosure and taken in conjunction with the accompanyingdrawings wherein:

[0011]FIG. 1 is a plan view of a prior art integrated circuit die havingbond pads thereon connected with bond wires to respective ones of innerleads of a leadframe;

[0012]FIG. 2 is a plan view of a prior art integrated circuit die havingtwo bond pads thereon connected with two bond wires to a common innerlead of a leadframe;

[0013]FIG. 3 is a plan view of a prior art integrated circuit die havingtwo bond pads thereon connected with an internal metal mask jumper;

[0014]FIG. 4 is a plan view of an integrated circuit die having two bondpads and an inner lead of a leadframe connected together with a singlestitch bond connected bond wire, and two other inner leads of theleadframe connected to another bond pad with another single stitch bondconnected bond wire, according to exemplary embodiments of the presentinvention;

[0015]FIG. 5 is a plan view of the integrated circuit die illustrated inFIG. 4 with the addition of a device mode selection jumper commonlyconnecting mode option selection bond pads on the die, according toanother exemplary embodiment of the present invention; and

[0016]FIG. 6 is an elevational view of a single stitch bond connectedbond wire, according to the exemplary embodiments of the presentinvention.

[0017] While the present invention is susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawing and are hereindescribed in detail. It should be understood, however, that thedescription herein of specific embodiments is not intended to limit theinvention to the particular forms disclosed, but on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0018] The present invention provides multiple common connections in anintegrated device while requiring only a single connection point at eachof the commonly connected integrated circuit die bond pads and/or innerleads of a leadframe. A multiple common connection is provided by usinga single bond wire which is stitch or wedge bonded to a single point ateach die bond pad and inner lead of the leadframe that are commonlyconnected together.

[0019] Referring now to the drawings, the details of exemplaryembodiments of the present invention are schematically illustrated. Likeelements in the drawings will be represented by like numbers, andsimilar elements will be represented by like numbers with a differentlower case letter suffix.

[0020] The term “wirebonding” is generally accepted to mean theinterconnection (via wire) of components, contact pads and conductingtracks. There are two basic wirebonding techniques that may be used inthermocompression (T/C), thermosonic (T/S) or ultrasonic (U/S) bondingprocesses, they are ball bonding and wedge bonding. Referring to FIG. 1,in ball bonding a wire, e.g., bond wire 110, is passed through a hollowcapillary tool (not shown) and a small portion of the end of this wireis heated to a molten condition wherein the surface tension of themolten metal forms a spherical shape, or ball, as the bond wire materialsolidifies. The ball at the end of the wire is pressed onto a bond pad104 of the semiconductor die 102 with sufficient force to cause plasticdeformation and atomic interdiffusion of the ball and the underlyingmetallization of the bond pad 104. This creates a low resistanceconnection between the bond pad 104 and the ball at the end of the wire.

[0021] The capillary tool containing the wire is then raised andrepositioned over the next connection point, e.g., inner lead 106 of theleadframe. A precisely shaped wire connection called a wire loop is thuscreated. Deforming the wire against the inner lead 106 makes the secondbond (e.g., wedge bond or stitch bond). The deformation of the wireagainst the inner lead 106 may have a crescent or fishtail shape made bythe imprint of the capillary tool's outer geometry. After this secondconnection is made, the wire is clamped and then broken off after thebond connection.

[0022] Wedge bonding derives its name from the shape of the bondingcapillary tool. In wedge bonding, the wire is fed at an angle from about30-60 degrees from the horizontal bonding surface through a hole in theback of a bonding wedge of the capillary tool. Normally, forward bondingis preferred, i.e., the first bond is made to the die bond pad 104 andthe second bond is made to the inner lead 106 of the leadframe. Afterthe first bond operation, the wedge bonding capillary tool rises andexecutes a motion to create a desired wire loop shape (bond wire). Atthe second bond location, the wedge bonding capillary tool descends andmakes the second bond connection. The movement of the axis of the wedgebonding capillary tool allows the wire to freely feed through the holein the wedge bonding capillary tool. The bonded wire may be separatedfrom the wire remaining in the wedge bonding capillary tool by usingclamps to break the wire while machine bonding force is maintained onthe second bond (clamp tear), or the clamp remains stationary and thewedge bonding capillary tool raises off the second bond area to tear thewire apart (table tear).

[0023] The wire is made of a conductive material such as metal, e.g.,gold, copper, aluminum, combinations of these metals (alloys), or alloysof these metals in combination with other metals, e.g., Silicon (Si)and/or magnesium (Mg). The bonding surfaces may be coated or plated witha compatible conductive material, e.g., gold, aluminum, gold, or nickel,etc. It is contemplated and within the scope of the present inventionthat any type of conductive material, e.g., metal or metal alloy iswithin the scope of the present invention.

[0024]FIG. 1 depicts is a plan view of a prior art integrated circuitdie having bond pads thereon connected with bond wires to respectiveones of inner leads of a leadframe. The integrated circuit die isrepresented by the numeral 102 and has a plurality of bond pads 104thereon. The bond pads 104 are connected to the electronic circuits (notshown) comprising the die 102. A leadframe (not entirely shown, but wellknown to those skilled in the art of integrated circuits) comprises aplurality of inner leads 106, a plurality of outer leads 108 and asupport structure or “die paddle” (not shown). The die 102 is initiallysupported by the leadframe die paddle. The outer leads 108 may be formedinto connecting pins or surface mount contacts as desired. Bond wires110 electrically connect the bond pads 104 to respective ones of theinner leads 106. The die 102 and supporting die paddle, bond pads 104,inner leads 106 and bond wires 110 may be encapsulated in an integratedcircuit package, schematically depicted by the outline referenced by thenumeral 112.

[0025] Referring to FIG. 2, depicted is a plan view of a prior artintegrated circuit die having two bond pads thereon connected with twobond wires to a common inner lead of a leadframe. Two bond wires 110 aand 110 b are attached to the inner lead 106 a and thereby electricallyinterconnect bond pad 104 a, bond pad 104 b and the inner lead 106 atogether. A problem exists however in that the inner lead 106 a musthave sufficient free bonding area to accommodate two bond wireconnections. When more than two interconnections are required, thisbonding area problem is further exasperated. As semiconductor integratedcircuit devices become smaller and more complex, there may not besufficient bonding area on an inner lead or bond pad to accommodate morethan one bond wire connection.

[0026] Referring to FIG. 3, depicted is a plan view of a prior artintegrated circuit die having two bond pads thereon connected with aninternal metal mask jumper. During fabrication of the semiconductorintegrated circuit die 102 a, a conductive jumper 310 may be createdduring a metallization step in the die fabrication process so as tointerconnect, for example, bond pads 104 a and 104 b. The jumper 310 maybe used to configure or set options within the die 102 a, however,different metallization masks and batch runs must be performed duringthe integrated circuit die fabrication process to achieve thesedifferent integrated circuit options. Thus, a using mask jumper(s) 310is not cost effective for a small quantity of semiconductor devices. Inaddition, a greater parts inventory is required when using mask jumperssince larger quantities of each semiconductor die configuration must befabricated in order to be cost effective.

[0027] Referring now to FIG. 4, depicted is a plan view of an integratedcircuit die having two bond pads and an inner lead of a leadframeconnected together with a single stitch bond connected bond wire, andtwo other inner leads of the leadframe connected to another bond padwith another single stitch bond connected bond wire, according toexemplary embodiments of the present invention. A single bond wire 410 aconnects bond pad 1 04 a, inner lead 1 06 a and inner lead 1 06 btogether and requires only one bond point a each connection area of thebond pad 104 a, inner lead 106 a and inner lead 106 b. A ball or wedgebond connection may be used at the first connection point of the bondwire 410 a, and subsequent connection points may use wedge (stitch)bonding. The bond wire 410 a remains unbroken (continuous) until thelast connection has been made. The first connection of the bond wire 410a may begin at either bond pad 104 a or inner lead 106 b. Preferably,the first connection will be at the bond pad 104 a. The intermediateconnection at the inner lead 106 a will be a wedge (stitch) bond whereinthe bond wire 410 a remains unbroken. For example, a simpleinterconnection operation may be performed as follows. First, thecapillary tool bonds the bond wire 410 a to the bond pad 104 a of thedie 102, then the capillary tool moves to the inner lead 106 a. A wedge(stitch) bond is made to the inner lead 106 a, and then the capillarytool moves to the inner lead 106 b and bonds the bond wire 410 athereto. In a similar fashion, bond wire 410 b may interconnect bond pad104 b, bond pad 104 c and inner lead 106 c together.

[0028] Referring now to FIG. 5, depicted is a plan view of theintegrated circuit die illustrated in FIG. 4 with the addition of adevice mode selection jumper commonly connecting mode option selectionbond pads on the die, according to another exemplary embodiment of thepresent invention. Bond pads 404 a, 404 b and 404 c are exemplary andmay be greater or fewer in number depending upon the application andnumber of operational modes that may be selected for the semiconductorintegrated circuit die 102 b. A stitch bonded jumper bond wire 510 mayconnect bond pads 404 a, 404 b and 404 c together. When a differentoption or die configuration is desired, the bond pads 404 a, 404 b and404 c may be interconnected or left unconnected as required.

[0029]FIG. 6 is an elevational view of a single stitch bond connectedbond wire, according to the exemplary embodiments of the presentinvention. The first connection of the bond wire 410 b may begin ateither bond pad 104 a or inner lead 106. Preferably, the firstconnection will be at the bond pad 104 a. A connection to bond pad 104 bis made by stitch bonding the bond wire 410 b which remains unbroken orcontinuous until bonded to the inner lead 106. After the bond wire 410 bhas been bonded to the inner lead 106, it is separated from the wire atthe tip of the capillary tool, thus completing the stitch bond.

[0030] The invention, therefore, is well adapted to carry out theobjects and attain the ends and advantages mentioned, as well as othersinherent therein. While the invention has been depicted, described, andis defined by reference to exemplary embodiments of the invention, suchreferences do not imply a limitation on the invention, and no suchlimitation is to be inferred. The invention is capable of considerablemodification, alternation, and equivalents in form and function, as willoccur to those ordinarily skilled in the pertinent arts and having thebenefit of this disclosure. The depicted and described embodiments ofthe invention are exemplary only, and are not exhaustive of the scope ofthe invention Consequently, the invention is intended to be limited onlyby the spirit and scope of the appended claims, giving fill cognizanceto equivalents in all respects.

What is claimed is:
 1. An integrated circuit device, comprising: aleadframe having a plurality of inner leads; and an integrated circuitdie having a plurality of bond pads; wherein at least two of theplurality of bond pads and at least one of the plurality of inner leadsare electrically coupled together with a single bond wire.
 2. Theintegrated circuit device of claim 1, wherein a first bond connection ofthe single bond wire is made with a ball bond and subsequent bondconnections are made with wedge bonds.
 3. The integrated circuit deviceof claim 1, wherein bond connections of the single bond wire are madewith wedge bonds.
 4. The integrated circuit device of claim 1, wherein afirst bond connection of the single bond wire is made at a one of the atleast two bond pads and a last bond connection of the single bond wireis made at the at least one inner lead.
 5. The integrated circuit deviceof claim 1, wherein a first bond connection of the single bond wire ismade at the at least one inner lead and a last bond connection of thesingle bond wire is made at a one of the at least two bond pads.
 6. Theintegrated circuit device of claim 1, further comprising an integratedcircuit package encapsulating the plurality of inner leads of theleadframe, the integrated circuit die, the plurality of bond pads andthe single bond wire.
 7. An integrated circuit device, comprising: aleadframe having a plurality of inner leads; and an integrated circuitdie having a plurality of bond pads; wherein at least one of theplurality of bond pads and at least two of the plurality of inner leadsare electrically coupled together with a single bond wire.
 8. Theintegrated circuit device of claim 7, wherein a first bond connection ofthe single bond wire is made with a ball bond and subsequent bondconnections are made with wedge bonds.
 9. The integrated circuit deviceof claim 7, wherein bond connections of the single bond wire are madewith wedge bonds.
 10. The integrated circuit device of claim 7, whereina first bond connection of the single bond wire is made at the at leastone of the plurality of bond pads and a last bond connection of thesingle bond wire is made at a one of the at least two inner leads. 11.The integrated circuit device of claim 7, wherein a first bondconnection of the single bond wire is made at a one of the at least twoinner leads and a last bond connection of the single bond wire is madeat the at least one of the plurality of bond pads.
 12. The integratedcircuit device of claim 7, further comprising an integrated circuitpackage encapsulating the plurality of inner leads of the leadframe, theintegrated circuit die, the plurality of bond pads and the single bondwire.
 13. An integrated circuit device, comprising: an integratedcircuit die having a plurality of first bond pads and a plurality ofsecond bond pads; wherein at least three of the plurality of second bondpads are electrically coupled together with a single bond wire.
 14. Theintegrated circuit device of claim 13, wherein a first bond connectionof the single bond wire is made with a ball bond and subsequent bondconnections are made with wedge bonds.
 15. The integrated circuit deviceof claim 13, wherein bond connections of the single bond wire are madewith wedge bonds.
 16. The integrated circuit device of claim 13, whereinoptions of the integrated circuit die are configured by couplingselected ones of the plurality of second bond pads with the single bondwire.
 17. The integrated circuit device of claim 13, further comprisingan integrated circuit package encapsulating the integrated circuit die,the plurality of first and second bond pads, and the single bond wire.18. A method of making electrical connections between an integratedcircuit die and a leadframe with a single bond wire, said methodcomprising the steps of: providing a leadframe having a plurality ofinner leads; providing an integrated circuit die having a plurality ofbond pads; and coupling together at least two of the plurality of bondpads and at least one of the plurality of inner leads with a single bondwire.
 19. The method of claim 18, wherein the step of coupling comprisesthe steps of: making a first bond connection with a ball bond; andmaking subsequent bond connections with wedge bonds.
 20. The method ofclaim 18, wherein the step of coupling comprises the steps of makingwedge bond connections with the single bond wire to the at least two ofthe plurality of bond pads and the at least one of the plurality ofinner leads.
 21. The method of claim 18, wherein the step of couplingcomprises the steps of: making a first bond connection of the singlebond wire at a one of the at least two bond pads; and making a last bondconnection of the single bond wire at the at least one inner lead. 22.The method of claim 18, wherein the step of coupling comprises the stepsof: making a first bond connection of the single bond wire at the atleast one inner lead; and making a last bond connection of the singlebond wire at a one of the at least two bond pads.
 23. A method of makingelectrical connections between an integrated circuit die and a leadframewith a single bond wire, said method comprising the steps of: providinga leadframe having a plurality of inner leads; providing an integratedcircuit die having a plurality of bond pads; and coupling together atleast one of the plurality of bond pads and at least two of theplurality of inner leads with a single bond wire.
 24. The integratedcircuit device of claim 23, wherein the step of coupling comprises thesteps of: making a first bond connection with a ball bond; and makingsubsequent bond connections with wedge bonds.
 25. The method of claim23, wherein the step of coupling comprises the steps of making wedgebond connections with the single bond wire to the at least one of theplurality of bond pads and the at least two of the plurality of innerleads.
 26. The method of claim 23, wherein the step of couplingcomprises the steps of: making a first bond connection of the singlebond wire at the at least one of the plurality of bond pads; and makinga last bond connection of the single bond wire at a one of the at leasttwo inner leads.
 27. The method of claim 23, wherein the step ofcoupling comprises the steps of: making a first bond connection of thesingle bond wire at a one of the at least two inner leads; and making alast bond connection of the single bond wire at the at least one of theplurality of bond pads.
 28. A method of making electrical connections onan integrated circuit die with a single bond wire, said methodcomprising the steps of: providing an integrated circuit die having aplurality of bond pads; and coupling together at least three of theplurality of bond pads with a single bond wire.
 29. The method of claim28, wherein the step of coupling comprises the steps of: making a firstbond connection of the single bond wire with a ball bond; and makingsubsequent bond connections with wedge bonds.
 30. The method of claim28, wherein the step of coupling comprises the steps of making wedgebond connections with the single bond wire.
 31. The method of claim 28,further comprising the step of configuring options of the integratedcircuit die by coupling selected ones of the plurality of bond pads withthe single bond wire.